networking/inetd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*      $Slackware: inetd.c 1.79s 2001/02/06 13:18:00 volkerdi Exp $    */
   3 /*      $OpenBSD: inetd.c,v 1.79 2001/01/30 08:30:57 deraadt Exp $      */
   4 /*      $NetBSD: inetd.c,v 1.11 1996/02/22 11:14:41 mycroft Exp $       */
   5 /* Busybox port by Vladimir Oleynik (C) 2001-2005 <dzo@simtreas.ru>     */
   6 /*
   7  * Copyright (c) 1983,1991 The Regents of the University of California.
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 /* Inetd - Internet super-server
  40  *
  41  * This program invokes all internet services as needed.
  42  * connection-oriented services are invoked each time a
  43  * connection is made, by creating a process.  This process
  44  * is passed the connection as file descriptor 0 and is
  45  * expected to do a getpeername to find out the source host
  46  * and port.
  47  *
  48  * Datagram oriented services are invoked when a datagram
  49  * arrives; a process is created and passed a pending message
  50  * on file descriptor 0.  Datagram servers may either connect
  51  * to their peer, freeing up the original socket for inetd
  52  * to receive further messages on, or "take over the socket",
  53  * processing all arriving datagrams and, eventually, timing
  54  * out.  The first type of server is said to be "multi-threaded";
  55  * the second type of server "single-threaded".
  56  *
  57  * Inetd uses a configuration file which is read at startup
  58  * and, possibly, at some later time in response to a hangup signal.
  59  * The configuration file is "free format" with fields given in the
  60  * order shown below.  Continuation lines for an entry must begin with
  61  * a space or tab.  All fields must be present in each entry.
  62  *
  63  *      service name                    must be in /etc/services
  64  *      socket type                     stream/dgram/raw/rdm/seqpacket
  65  *      protocol                        must be in /etc/protocols
  66  *      wait/nowait[.max]               single-threaded/multi-threaded, max #
  67  *      user[.group] or user[:group]    user/group to run daemon as
  68  *      server program                  full path name
  69  *      server program arguments        maximum of MAXARGS (20)
  70  *
  71  * For RPC services
  72  *      service name/version            must be in /etc/rpc
  73  *      socket type                     stream/dgram/raw/rdm/seqpacket
  74  *      protocol                        must be in /etc/protocols
  75  *      wait/nowait[.max]               single-threaded/multi-threaded
  76  *      user[.group] or user[:group]    user to run daemon as
  77  *      server program                  full path name
  78  *      server program arguments        maximum of MAXARGS (20)
  79  *
  80  * For non-RPC services, the "service name" can be of the form
  81  * hostaddress:servicename, in which case the hostaddress is used
  82  * as the host portion of the address to listen on.  If hostaddress
  83  * consists of a single `*' character, INADDR_ANY is used.
  84  *
  85  * A line can also consist of just
  86  *      hostaddress:
  87  * where hostaddress is as in the preceding paragraph.  Such a line must
  88  * have no further fields; the specified hostaddress is remembered and
  89  * used for all further lines that have no hostaddress specified,
  90  * until the next such line (or EOF).  (This is why * is provided to
  91  * allow explicit specification of INADDR_ANY.)  A line
  92  *      *:
  93  * is implicitly in effect at the beginning of the file.
  94  *
  95  * The hostaddress specifier may (and often will) contain dots;
  96  * the service name must not.
  97  *
  98  * For RPC services, host-address specifiers are accepted and will
  99  * work to some extent; however, because of limitations in the
 100  * portmapper interface, it will not work to try to give more than
 101  * one line for any given RPC service, even if the host-address
 102  * specifiers are different.
 103  *
 104  * Comment lines are indicated by a `#' in column 1.
 105  */
 106
 107 /* inetd rules for passing file descriptors to children
 108  * (http://www.freebsd.org/cgi/man.cgi?query=inetd):
 109  *
 110  * The wait/nowait entry specifies whether the server that is invoked by
 111  * inetd will take over the socket associated with the service access point,
 112  * and thus whether inetd should wait for the server to exit before listen-
 113  * ing for new service requests.  Datagram servers must use "wait", as
 114  * they are always invoked with the original datagram socket bound to the
 115  * specified service address.  These servers must read at least one datagram
 116  * from the socket before exiting.  If a datagram server connects to its
 117  * peer, freeing the socket so inetd can receive further messages on the
 118  * socket, it is said to be a "multi-threaded" server; it should read one
 119  * datagram from the socket and create a new socket connected to the peer.
 120  * It should fork, and the parent should then exit to allow inetd to check
 121  * for new service requests to spawn new servers.  Datagram servers which
 122  * process all incoming datagrams on a socket and eventually time out are
 123  * said to be "single-threaded".  The comsat(8), (biff(1)) and talkd(8)
 124  * utilities are both examples of the latter type of datagram server.  The
 125  * tftpd(8) utility is an example of a multi-threaded datagram server.
 126  *
 127  * Servers using stream sockets generally are multi-threaded and use the
 128  * "nowait" entry. Connection requests for these services are accepted by
 129  * inetd, and the server is given only the newly-accepted socket connected
 130  * to a client of the service.  Most stream-based services operate in this
 131  * manner.  Stream-based servers that use "wait" are started with the lis-
 132  * tening service socket, and must accept at least one connection request
 133  * before exiting.  Such a server would normally accept and process incoming
 134  * connection requests until a timeout.
 135  */
 136
 137 /* Here's the scoop concerning the user[.:]group feature:
 138  *
 139  * 1) set-group-option off.
 140  *
 141  *      a) user = root: NO setuid() or setgid() is done
 142  *
 143  *      b) other:       setgid(primary group as found in passwd)
 144  *                      initgroups(name, primary group)
 145  *                      setuid()
 146  *
 147  * 2) set-group-option on.
 148  *
 149  *      a) user = root: setgid(specified group)
 150  *                      NO initgroups()
 151  *                      NO setuid()
 152  *
 153  *      b) other:       setgid(specified group)
 154  *                      initgroups(name, specified group)
 155  *                      setuid()
 156  */
 157
 158 #include "busybox.h"
 159 #include <syslog.h>
 160 #include <sys/un.h>
 161
 162 //#define CONFIG_FEATURE_INETD_RPC
 163 //#define CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 164 //#define CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 165 //#define CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 166 //#define CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 167 //#define CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 168 //#define CONFIG_FEATURE_IPV6
 169
 170 #ifdef CONFIG_FEATURE_INETD_RPC
 171 #include <rpc/rpc.h>
 172 #include <rpc/pmap_clnt.h>
 173 #endif
 174
 175 #define _PATH_INETDCONF "/etc/inetd.conf"
 176 #define _PATH_INETDPID  "/var/run/inetd.pid"
 177
 178
 179 #define CNT_INTVL       60              /* servers in CNT_INTVL sec. */
 180 #define RETRYTIME       (60*10)         /* retry after bind or server fail */
 181
 182 #ifndef RLIMIT_NOFILE
 183 #define RLIMIT_NOFILE   RLIMIT_OFILE
 184 #endif
 185
 186 #ifndef OPEN_MAX
 187 #define OPEN_MAX        64
 188 #endif
 189
 190 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
 191 #define FD_MARGIN       8
 192 static rlim_t rlim_ofile_cur = OPEN_MAX;
 193 static struct rlimit rlim_ofile;
 194
 195
 196 /* Check unsupporting builtin */
 197 #if defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
 198                 defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD || \
 199                 defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_TIME || \
 200                 defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME || \
 201                 defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 202 # define INETD_FEATURE_ENABLED
 203 #endif
 204
 205 #if defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
 206                 defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD || \
 207                 defined CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 208 # define INETD_SETPROCTITLE
 209 #endif
 210
 211 typedef struct servtab {
 212         char *se_hostaddr;                    /* host address to listen on */
 213         char *se_service;                     /* name of service */
 214         int se_socktype;                      /* type of socket to use */
 215         int se_family;                        /* address family */
 216         char *se_proto;                       /* protocol used */
 217 #ifdef CONFIG_FEATURE_INETD_RPC
 218         int se_rpcprog;                       /* rpc program number */
 219         int se_rpcversl;                      /* rpc program lowest version */
 220         int se_rpcversh;                      /* rpc program highest version */
 221 #define isrpcservice(sep)       ((sep)->se_rpcversl != 0)
 222 #else
 223 #define isrpcservice(sep)       0
 224 #endif
 225         pid_t se_wait;                        /* single threaded server */
 226         short se_checked;                     /* looked at during merge */
 227         char *se_user;                        /* user name to run as */
 228         char *se_group;                       /* group name to run as */
 229 #ifdef INETD_FEATURE_ENABLED
 230         const struct builtin *se_bi;          /* if built-in, description */
 231 #endif
 232         char *se_server;                      /* server program */
 233 #define MAXARGV 20
 234         char *se_argv[MAXARGV + 1];           /* program arguments */
 235         int se_fd;                            /* open descriptor */
 236         union {
 237                 struct sockaddr se_un_ctrladdr;
 238                 struct sockaddr_in se_un_ctrladdr_in;
 239 #ifdef CONFIG_FEATURE_IPV6
 240                 struct sockaddr_in6 se_un_ctrladdr_in6;
 241 #endif
 242                 struct sockaddr_un se_un_ctrladdr_un;
 243         } se_un;                              /* bound address */
 244 #define se_ctrladdr     se_un.se_un_ctrladdr
 245 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 246 #define se_ctrladdr_in6 se_un.se_un_ctrladdr_in6
 247 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 248         int se_ctrladdr_size;
 249         int se_max;                           /* max # of instances of this service */
 250         int se_count;                         /* number started since se_time */
 251         struct timeval se_time;               /* start of se_count */
 252         struct servtab *se_next;
 253 } servtab_t;
 254
 255 static servtab_t *servtab;
 256
 257 #ifdef INETD_FEATURE_ENABLED
 258 struct builtin {
 259         const char *bi_service;               /* internally provided service name */
 260         int bi_socktype;                      /* type of socket supported */
 261         short bi_fork;                        /* 1 if should fork before call */
 262         short bi_wait;                        /* 1 if should wait for child */
 263         void (*bi_fn) (int, servtab_t *);
 264 };
 265
 266                 /* Echo received data */
 267 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 268 static void echo_stream(int, servtab_t *);
 269 static void echo_dg(int, servtab_t *);
 270 #endif
 271                 /* Internet /dev/null */
 272 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 273 static void discard_stream(int, servtab_t *);
 274 static void discard_dg(int, servtab_t *);
 275 #endif
 276                 /* Return 32 bit time since 1900 */
 277 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 278 static void machtime_stream(int, servtab_t *);
 279 static void machtime_dg(int, servtab_t *);
 280 #endif
 281                 /* Return human-readable time */
 282 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 283 static void daytime_stream(int, servtab_t *);
 284 static void daytime_dg(int, servtab_t *);
 285 #endif
 286                 /* Familiar character generator */
 287 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 288 static void chargen_stream(int, servtab_t *);
 289 static void chargen_dg(int, servtab_t *);
 290 #endif
 291
 292 static const struct builtin builtins[] = {
 293 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 294         /* Echo received data */
 295         {"echo", SOCK_STREAM, 1, 0, echo_stream,},
 296         {"echo", SOCK_DGRAM, 0, 0, echo_dg,},
 297 #endif
 298 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 299         /* Internet /dev/null */
 300         {"discard", SOCK_STREAM, 1, 0, discard_stream,},
 301         {"discard", SOCK_DGRAM, 0, 0, discard_dg,},
 302 #endif
 303 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 304         /* Return 32 bit time since 1900 */
 305         {"time", SOCK_STREAM, 0, 0, machtime_stream,},
 306         {"time", SOCK_DGRAM, 0, 0, machtime_dg,},
 307 #endif
 308 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 309         /* Return human-readable time */
 310         {"daytime", SOCK_STREAM, 0, 0, daytime_stream,},
 311         {"daytime", SOCK_DGRAM, 0, 0, daytime_dg,},
 312 #endif
 313 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 314         /* Familiar character generator */
 315         {"chargen", SOCK_STREAM, 1, 0, chargen_stream,},
 316         {"chargen", SOCK_DGRAM, 0, 0, chargen_dg,},
 317 #endif
 318         {NULL, 0, 0, 0, NULL}
 319 };
 320 #endif /* INETD_FEATURE_ENABLED */
 321
 322 static int global_queuelen = 128;
 323 static int nsock, maxsock;
 324 static fd_set allsock;
 325 static int toomany;
 326 static int timingout;
 327 static struct servent *sp;
 328 static uid_t uid;
 329
 330 static char *CONFIG = _PATH_INETDCONF;
 331
 332 static FILE *fconfig;
 333 static char line[1024];
 334 static char *defhost;
 335
 336 /* xstrdup(NULL) returns NULL, but this one
 337  * will return newly-allocated "" if called with NULL arg
 338  * TODO: audit whether this makes any real difference
 339  */
 340 static char *xxstrdup(char *cp)
 341 {
 342         return xstrdup(cp ? cp : "");
 343 }
 344
 345 static int setconfig(void)
 346 {
 347         free(defhost);
 348         defhost = xstrdup("*");
 349         if (fconfig != NULL) {
 350                 fseek(fconfig, 0L, SEEK_SET);
 351                 return 1;
 352         }
 353         fconfig = fopen(CONFIG, "r");
 354         return (fconfig != NULL);
 355 }
 356
 357 static void endconfig(void)
 358 {
 359         if (fconfig) {
 360                 (void) fclose(fconfig);
 361                 fconfig = NULL;
 362         }
 363         free(defhost);
 364         defhost = 0;
 365 }
 366
 367 #ifdef CONFIG_FEATURE_INETD_RPC
 368 static void register_rpc(servtab_t *sep)
 369 {
 370         int n;
 371         struct sockaddr_in ir_sin;
 372         struct protoent *pp;
 373         socklen_t size;
 374
 375         if ((pp = getprotobyname(sep->se_proto + 4)) == NULL) {
 376                 bb_perror_msg("%s: getproto", sep->se_proto);
 377                 return;
 378         }
 379         size = sizeof ir_sin;
 380         if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
 381                 bb_perror_msg("%s/%s: getsockname",
 382                                 sep->se_service, sep->se_proto);
 383                 return;
 384         }
 385
 386         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 387                 (void) pmap_unset(sep->se_rpcprog, n);
 388                 if (!pmap_set(sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port)))
 389                         bb_perror_msg("%s %s: pmap_set: %u %u %u %u",
 390                                         sep->se_service, sep->se_proto,
 391                                         sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port));
 392         }
 393 }
 394
 395 static void unregister_rpc(servtab_t *sep)
 396 {
 397         int n;
 398
 399         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 400                 if (!pmap_unset(sep->se_rpcprog, n))
 401                         bb_error_msg("pmap_unset(%u, %u)", sep->se_rpcprog, n);
 402         }
 403 }
 404 #endif /* CONFIG_FEATURE_INETD_RPC */
 405
 406 static void freeconfig(servtab_t *cp)
 407 {
 408         int i;
 409
 410         free(cp->se_hostaddr);
 411         free(cp->se_service);
 412         free(cp->se_proto);
 413         free(cp->se_user);
 414         free(cp->se_group);
 415         free(cp->se_server);
 416         for (i = 0; i < MAXARGV; i++)
 417                 free(cp->se_argv[i]);
 418 }
 419
 420 static int bump_nofile (void)
 421 {
 422 #define FD_CHUNK        32
 423
 424         struct rlimit rl;
 425
 426         if (getrlimit (RLIMIT_NOFILE, &rl) < 0) {
 427                 bb_perror_msg("getrlimit");
 428                 return -1;
 429         }
 430         rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
 431         rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
 432         if (rl.rlim_cur <= rlim_ofile_cur) {
 433                 bb_error_msg("bump_nofile: cannot extend file limit, max = %d",
 434                                                 (int) rl.rlim_cur);
 435                 return -1;
 436         }
 437
 438         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 439                 bb_perror_msg("setrlimit");
 440                 return -1;
 441         }
 442
 443         rlim_ofile_cur = rl.rlim_cur;
 444         return 0;
 445 }
 446
 447 static void setup(servtab_t *sep)
 448 {
 449         int r;
 450
 451         sep->se_fd = socket(sep->se_family, sep->se_socktype, 0);
 452         if (sep->se_fd < 0) {
 453                 bb_perror_msg("%s/%s: socket", sep->se_service, sep->se_proto);
 454                 return;
 455         }
 456         if (setsockopt_reuseaddr(sep->se_fd) < 0)
 457                 bb_perror_msg("setsockopt(SO_REUSEADDR)");
 458
 459 #ifdef CONFIG_FEATURE_INETD_RPC
 460         if (isrpcservice(sep)) {
 461                 struct passwd *pwd;
 462
 463                 /*
 464                  * for RPC services, attempt to use a reserved port
 465                  * if they are going to be running as root.
 466                  *
 467                  * Also, zero out the port for all RPC services; let bind()
 468                  * find one.
 469                  */
 470                 sep->se_ctrladdr_in.sin_port = 0;
 471                 if (sep->se_user && (pwd = getpwnam(sep->se_user)) &&
 472                                 pwd->pw_uid == 0 && uid == 0)
 473                         r = bindresvport(sep->se_fd, &sep->se_ctrladdr_in);
 474                 else {
 475                         r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 476                         if (r == 0) {
 477                                 socklen_t len = sep->se_ctrladdr_size;
 478                                 int saveerrno = errno;
 479
 480                                 /* update se_ctrladdr_in.sin_port */
 481                                 r = getsockname(sep->se_fd, &sep->se_ctrladdr, &len);
 482                                 if (r <= 0)
 483                                         errno = saveerrno;
 484                         }
 485                 }
 486         } else
 487 #endif
 488                 r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 489         if (r < 0) {
 490                 bb_perror_msg("%s/%s (%d): bind",
 491                                 sep->se_service, sep->se_proto, sep->se_ctrladdr.sa_family);
 492                 close(sep->se_fd);
 493                 sep->se_fd = -1;
 494                 if (!timingout) {
 495                         timingout = 1;
 496                         alarm(RETRYTIME);
 497                 }
 498                 return;
 499         }
 500         if (sep->se_socktype == SOCK_STREAM)
 501                 listen(sep->se_fd, global_queuelen);
 502
 503         FD_SET(sep->se_fd, &allsock);
 504         nsock++;
 505         if (sep->se_fd > maxsock) {
 506                 maxsock = sep->se_fd;
 507                 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
 508                         bump_nofile();
 509         }
 510 }
 511
 512 static char *nextline(void)
 513 {
 514         char *cp;
 515         FILE *fd = fconfig;
 516
 517         if (fgets(line, sizeof(line), fd) == NULL)
 518                 return NULL;
 519         cp = strchr(line, '\n');
 520         if (cp)
 521                 *cp = '\0';
 522         return line;
 523 }
 524
 525 static char *skip(char **cpp) /* int report; */
 526 {
 527         char *cp = *cpp;
 528         char *start;
 529
 530 /* erp: */
 531         if (*cpp == NULL) {
 532                 /* if (report) */
 533                 /* bb_error_msg("syntax error in inetd config file"); */
 534                 return NULL;
 535         }
 536
 537 again:
 538         while (*cp == ' ' || *cp == '\t')
 539                 cp++;
 540         if (*cp == '\0') {
 541                 int c;
 542
 543                 c = getc(fconfig);
 544                 (void) ungetc(c, fconfig);
 545                 if (c == ' ' || c == '\t')
 546                         if ((cp = nextline()))
 547                                 goto again;
 548                 *cpp = NULL;
 549                 /* goto erp; */
 550                 return NULL;
 551         }
 552         start = cp;
 553         while (*cp && *cp != ' ' && *cp != '\t')
 554                 cp++;
 555         if (*cp != '\0')
 556                 *cp++ = '\0';
 557         /* if ((*cpp = cp) == NULL) */
 558         /* goto erp; */
 559
 560         *cpp = cp;
 561         return start;
 562 }
 563
 564 static servtab_t *new_servtab(void)
 565 {
 566         return xmalloc(sizeof(servtab_t));
 567 }
 568
 569 static servtab_t *dupconfig(servtab_t *sep)
 570 {
 571         servtab_t *newtab;
 572         int argc;
 573
 574         newtab = new_servtab();
 575         memset(newtab, 0, sizeof(servtab_t));
 576         newtab->se_service = xstrdup(sep->se_service);
 577         newtab->se_socktype = sep->se_socktype;
 578         newtab->se_family = sep->se_family;
 579         newtab->se_proto = xstrdup(sep->se_proto);
 580 #ifdef CONFIG_FEATURE_INETD_RPC
 581         newtab->se_rpcprog = sep->se_rpcprog;
 582         newtab->se_rpcversl = sep->se_rpcversl;
 583         newtab->se_rpcversh = sep->se_rpcversh;
 584 #endif
 585         newtab->se_wait = sep->se_wait;
 586         newtab->se_user = xstrdup(sep->se_user);
 587         newtab->se_group = xstrdup(sep->se_group);
 588 #ifdef INETD_FEATURE_ENABLED
 589         newtab->se_bi = sep->se_bi;
 590 #endif
 591         newtab->se_server = xstrdup(sep->se_server);
 592
 593         for (argc = 0; argc <= MAXARGV; argc++)
 594                 newtab->se_argv[argc] = xstrdup(sep->se_argv[argc]);
 595         newtab->se_max = sep->se_max;
 596
 597         return newtab;
 598 }
 599
 600 static servtab_t *getconfigent(void)
 601 {
 602         servtab_t *sep;
 603         int argc;
 604         char *cp, *arg;
 605         char *hostdelim;
 606         servtab_t *nsep;
 607         servtab_t *psep;
 608
 609         sep = new_servtab();
 610
 611         /* memset(sep, 0, sizeof *sep); */
 612  more:
 613         /* freeconfig(sep); */
 614
 615         while ((cp = nextline()) && *cp == '#') /* skip comment line */;
 616         if (cp == NULL) {
 617                 /* free(sep); */
 618                 return NULL;
 619         }
 620
 621         memset((char *) sep, 0, sizeof *sep);
 622         arg = skip(&cp);
 623         if (arg == NULL) {
 624                 /* A blank line. */
 625                 goto more;
 626         }
 627
 628         /* Check for a host name. */
 629         hostdelim = strrchr(arg, ':');
 630         if (hostdelim) {
 631                 *hostdelim = '\0';
 632                 sep->se_hostaddr = xstrdup(arg);
 633                 arg = hostdelim + 1;
 634                 /*
 635                  * If the line is of the form `host:', then just change the
 636                  * default host for the following lines.
 637                  */
 638                 if (*arg == '\0') {
 639                         arg = skip(&cp);
 640                         if (cp == NULL) {
 641                                 free(defhost);
 642                                 defhost = sep->se_hostaddr;
 643                                 goto more;
 644                         }
 645                 }
 646         } else
 647                 sep->se_hostaddr = xxstrdup(defhost);
 648
 649         sep->se_service = xxstrdup(arg);
 650         arg = skip(&cp);
 651
 652         if (strcmp(arg, "stream") == 0)
 653                 sep->se_socktype = SOCK_STREAM;
 654         else if (strcmp(arg, "dgram") == 0)
 655                 sep->se_socktype = SOCK_DGRAM;
 656         else if (strcmp(arg, "rdm") == 0)
 657                 sep->se_socktype = SOCK_RDM;
 658         else if (strcmp(arg, "seqpacket") == 0)
 659                 sep->se_socktype = SOCK_SEQPACKET;
 660         else if (strcmp(arg, "raw") == 0)
 661                 sep->se_socktype = SOCK_RAW;
 662         else
 663                 sep->se_socktype = -1;
 664
 665         sep->se_proto = xxstrdup(skip(&cp));
 666
 667         if (strcmp(sep->se_proto, "unix") == 0) {
 668                 sep->se_family = AF_UNIX;
 669         } else {
 670                 sep->se_family = AF_INET;
 671                 if (sep->se_proto[strlen(sep->se_proto) - 1] == '6')
 672 #ifdef CONFIG_FEATURE_IPV6
 673                         sep->se_family = AF_INET6;
 674 #else
 675                         bb_error_msg("%s: IPV6 not supported", sep->se_proto);
 676 #endif
 677                 if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
 678 #ifdef CONFIG_FEATURE_INETD_RPC
 679                         char *p, *ccp;
 680                         long l;
 681
 682                         p = strchr(sep->se_service, '/');
 683                         if (p == 0) {
 684                                 bb_error_msg("%s: no rpc version", sep->se_service);
 685                                 goto more;
 686                         }
 687                         *p++ = '\0';
 688                         l = strtol(p, &ccp, 0);
 689                         if (ccp == p || l < 0 || l > INT_MAX) {
 690                         badafterall:
 691                                 bb_error_msg("%s/%s: bad rpc version", sep->se_service, p);
 692                                 goto more;
 693                         }
 694                         sep->se_rpcversl = sep->se_rpcversh = l;
 695                         if (*ccp == '-') {
 696                                 p = ccp + 1;
 697                                 l = strtol(p, &ccp, 0);
 698                                 if (ccp == p || l < 0 || l > INT_MAX || l < sep->se_rpcversl || *ccp)
 699                                         goto badafterall;
 700                                 sep->se_rpcversh = l;
 701                         } else if (*ccp != '\0')
 702                                 goto badafterall;
 703 #else
 704                         bb_error_msg("%s: rpc services not supported", sep->se_service);
 705 #endif
 706                 }
 707         }
 708         arg = skip(&cp);
 709         if (arg == NULL)
 710                 goto more;
 711
 712         {
 713                 char *s = strchr(arg, '.');
 714                 if (s) {
 715                         *s++ = '\0';
 716                         sep->se_max = xatoi(s);
 717                 } else
 718                         sep->se_max = toomany;
 719         }
 720         sep->se_wait = strcmp(arg, "wait") == 0;
 721         /* if ((arg = skip(&cp, 1)) == NULL) */
 722         /* goto more; */
 723         sep->se_user = xxstrdup(skip(&cp));
 724         arg = strchr(sep->se_user, '.');
 725         if (arg == NULL)
 726                 arg = strchr(sep->se_user, ':');
 727         if (arg) {
 728                 *arg++ = '\0';
 729                 sep->se_group = xstrdup(arg);
 730         }
 731         /* if ((arg = skip(&cp, 1)) == NULL) */
 732         /* goto more; */
 733
 734         sep->se_server = xxstrdup(skip(&cp));
 735         if (strcmp(sep->se_server, "internal") == 0) {
 736 #ifdef INETD_FEATURE_ENABLED
 737                 const struct builtin *bi;
 738
 739                 for (bi = builtins; bi->bi_service; bi++)
 740                         if (bi->bi_socktype == sep->se_socktype &&
 741                                         strcmp(bi->bi_service, sep->se_service) == 0)
 742                                 break;
 743                 if (bi->bi_service == 0) {
 744                         bb_error_msg("internal service %s unknown", sep->se_service);
 745                         goto more;
 746                 }
 747                 sep->se_bi = bi;
 748                 sep->se_wait = bi->bi_wait;
 749 #else
 750                 bb_perror_msg("internal service %s unknown", sep->se_service);
 751                 goto more;
 752 #endif
 753         }
 754 #ifdef INETD_FEATURE_ENABLED
 755                 else
 756                 sep->se_bi = NULL;
 757 #endif
 758         argc = 0;
 759         for (arg = skip(&cp); cp; arg = skip(&cp)) {
 760                 if (argc < MAXARGV)
 761                         sep->se_argv[argc++] = xxstrdup(arg);
 762         }
 763         while (argc <= MAXARGV)
 764                 sep->se_argv[argc++] = NULL;
 765
 766         /*
 767          * Now that we've processed the entire line, check if the hostname
 768          * specifier was a comma separated list of hostnames. If so
 769          * we'll make new entries for each address.
 770          */
 771         while ((hostdelim = strrchr(sep->se_hostaddr, ',')) != NULL) {
 772                 nsep = dupconfig(sep);
 773
 774                 /*
 775                  * NULL terminate the hostname field of the existing entry,
 776                  * and make a dup for the new entry.
 777                  */
 778                 *hostdelim++ = '\0';
 779                 nsep->se_hostaddr = xstrdup(hostdelim);
 780
 781                 nsep->se_next = sep->se_next;
 782                 sep->se_next = nsep;
 783         }
 784
 785         nsep = sep;
 786         while (nsep != NULL) {
 787                 nsep->se_checked = 1;
 788                 if (nsep->se_family == AF_INET) {
 789                         if (LONE_CHAR(nsep->se_hostaddr, '*'))
 790                                 nsep->se_ctrladdr_in.sin_addr.s_addr = INADDR_ANY;
 791                         else if (!inet_aton(nsep->se_hostaddr, &nsep->se_ctrladdr_in.sin_addr)) {
 792                                 struct hostent *hp;
 793
 794                                 hp = gethostbyname(nsep->se_hostaddr);
 795                                 if (hp == 0) {
 796                                         bb_error_msg("%s: unknown host", nsep->se_hostaddr);
 797                                         nsep->se_checked = 0;
 798                                         goto skip;
 799                                 } else if (hp->h_addrtype != AF_INET) {
 800                                         bb_error_msg("%s: address isn't an Internet "
 801                                                                   "address", nsep->se_hostaddr);
 802                                         nsep->se_checked = 0;
 803                                         goto skip;
 804                                 } else {
 805                                         int i = 1;
 806
 807                                         memmove(&nsep->se_ctrladdr_in.sin_addr,
 808                                                                    hp->h_addr_list[0], sizeof(struct in_addr));
 809                                         while (hp->h_addr_list[i] != NULL) {
 810                                                 psep = dupconfig(nsep);
 811                                                 psep->se_hostaddr = xxstrdup(nsep->se_hostaddr);
 812                                                 psep->se_checked = 1;
 813                                                 memmove(&psep->se_ctrladdr_in.sin_addr,
 814                                                                      hp->h_addr_list[i], sizeof(struct in_addr));
 815                                                 psep->se_ctrladdr_size = sizeof(psep->se_ctrladdr_in);
 816                                                 i++;
 817                                                 /* Prepend to list, don't want to look up */
 818                                                 /* its hostname again. */
 819                                                 psep->se_next = sep;
 820                                                 sep = psep;
 821                                         }
 822                                 }
 823                         }
 824                 }
 825 /* XXX BUG?: is this skip: label supposed to remain? */
 826         skip:
 827                 nsep = nsep->se_next;
 828         }
 829
 830         /*
 831          * Finally, free any entries which failed the gethostbyname
 832          * check.
 833          */
 834         psep = NULL;
 835         nsep = sep;
 836         while (nsep != NULL) {
 837                 servtab_t *tsep;
 838
 839                 if (nsep->se_checked == 0) {
 840                         tsep = nsep;
 841                         if (psep == NULL) {
 842                                 sep = nsep->se_next;
 843                                 nsep = sep;
 844                         } else {
 845                                 nsep = nsep->se_next;
 846                                 psep->se_next = nsep;
 847                         }
 848                         freeconfig(tsep);
 849                 } else {
 850                         nsep->se_checked = 0;
 851                         psep = nsep;
 852                         nsep = nsep->se_next;
 853                 }
 854         }
 855
 856         return sep;
 857 }
 858
 859 #define Block_Using_Signals(m) do { \
 860         sigemptyset(&m); \
 861         sigaddset(&m, SIGCHLD); \
 862         sigaddset(&m, SIGHUP); \
 863         sigaddset(&m, SIGALRM); \
 864         sigprocmask(SIG_BLOCK, &m, NULL); \
 865 } while (0)
 866
 867 static servtab_t *enter(servtab_t *cp)
 868 {
 869         servtab_t *sep;
 870         sigset_t omask;
 871
 872         sep = new_servtab();
 873         *sep = *cp;
 874         sep->se_fd = -1;
 875 #ifdef CONFIG_FEATURE_INETD_RPC
 876         sep->se_rpcprog = -1;
 877 #endif
 878         Block_Using_Signals(omask);
 879         sep->se_next = servtab;
 880         servtab = sep;
 881         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 882         return sep;
 883 }
 884
 885 static int matchconf(servtab_t *old, servtab_t *new)
 886 {
 887         if (strcmp(old->se_service, new->se_service) != 0)
 888                 return 0;
 889
 890         if (strcmp(old->se_hostaddr, new->se_hostaddr) != 0)
 891                 return 0;
 892
 893         if (strcmp(old->se_proto, new->se_proto) != 0)
 894                 return 0;
 895
 896         /*
 897          * If the new servtab is bound to a specific address, check that the
 898          * old servtab is bound to the same entry. If the new service is not
 899          * bound to a specific address then the check of se_hostaddr above
 900          * is sufficient.
 901          */
 902
 903         if (old->se_family == AF_INET && new->se_family == AF_INET &&
 904                         memcmp(&old->se_ctrladdr_in.sin_addr,
 905                                         &new->se_ctrladdr_in.sin_addr,
 906                                         sizeof(new->se_ctrladdr_in.sin_addr)) != 0)
 907                 return 0;
 908
 909 #ifdef CONFIG_FEATURE_IPV6
 910         if (old->se_family == AF_INET6 && new->se_family == AF_INET6 &&
 911                         memcmp(&old->se_ctrladdr_in6.sin6_addr,
 912                                         &new->se_ctrladdr_in6.sin6_addr,
 913                                         sizeof(new->se_ctrladdr_in6.sin6_addr)) != 0)
 914                 return 0;
 915 #endif
 916         return 1;
 917 }
 918
 919 static void config(int sig ATTRIBUTE_UNUSED)
 920 {
 921         servtab_t *sep, *cp, **sepp;
 922         sigset_t omask;
 923         size_t n;
 924         char protoname[10];
 925
 926         if (!setconfig()) {
 927                 bb_perror_msg("%s", CONFIG);
 928                 return;
 929         }
 930         for (sep = servtab; sep; sep = sep->se_next)
 931                 sep->se_checked = 0;
 932         cp = getconfigent();
 933         while (cp != NULL) {
 934                 for (sep = servtab; sep; sep = sep->se_next)
 935                         if (matchconf(sep, cp))
 936                                 break;
 937
 938                 if (sep != 0) {
 939                         int i;
 940
 941 #define SWAP(type, a, b) do {type c=(type)a; a=(type)b; b=(type)c;} while (0)
 942
 943                         Block_Using_Signals(omask);
 944                         /*
 945                          * sep->se_wait may be holding the pid of a daemon
 946                          * that we're waiting for.  If so, don't overwrite
 947                          * it unless the config file explicitly says don't
 948                          * wait.
 949                          */
 950                         if (
 951 #ifdef INETD_FEATURE_ENABLED
 952                                 cp->se_bi == 0 &&
 953 #endif
 954                                 (sep->se_wait == 1 || cp->se_wait == 0))
 955                                 sep->se_wait = cp->se_wait;
 956                         SWAP(int, cp->se_max, sep->se_max);
 957                         SWAP(char *, sep->se_user, cp->se_user);
 958                         SWAP(char *, sep->se_group, cp->se_group);
 959                         SWAP(char *, sep->se_server, cp->se_server);
 960                         for (i = 0; i < MAXARGV; i++)
 961                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 962 #undef SWAP
 963
 964 #ifdef CONFIG_FEATURE_INETD_RPC
 965                         if (isrpcservice(sep))
 966                                 unregister_rpc(sep);
 967                         sep->se_rpcversl = cp->se_rpcversl;
 968                         sep->se_rpcversh = cp->se_rpcversh;
 969 #endif
 970                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 971                         freeconfig(cp);
 972                 } else {
 973                         sep = enter(cp);
 974                 }
 975                 sep->se_checked = 1;
 976
 977                 switch (sep->se_family) {
 978                 case AF_UNIX:
 979                         if (sep->se_fd != -1)
 980                                 break;
 981                         (void) unlink(sep->se_service);
 982                         n = strlen(sep->se_service);
 983                         if (n > sizeof sep->se_ctrladdr_un.sun_path - 1)
 984                                 n = sizeof sep->se_ctrladdr_un.sun_path - 1;
 985                         safe_strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n + 1);
 986                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 987                         sep->se_ctrladdr_size = n + sizeof sep->se_ctrladdr_un.sun_family;
 988                         setup(sep);
 989                         break;
 990                 case AF_INET:
 991                         sep->se_ctrladdr_in.sin_family = AF_INET;
 992                         /* se_ctrladdr_in was set in getconfigent */
 993                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 994
 995 #ifdef CONFIG_FEATURE_INETD_RPC
 996                         if (isrpcservice(sep)) {
 997                                 struct rpcent *rp;
 998                                 // FIXME: atoi_or_else(str, 0) would be handy here
 999                                 sep->se_rpcprog = atoi(sep->se_service);
1000                                 if (sep->se_rpcprog == 0) {
1001                                         rp = getrpcbyname(sep->se_service);
1002                                         if (rp == 0) {
1003                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1004                                                 goto serv_unknown;
1005                                         }
1006                                         sep->se_rpcprog = rp->r_number;
1007                                 }
1008                                 if (sep->se_fd == -1)
1009                                         setup(sep);
1010                                 if (sep->se_fd != -1)
1011                                         register_rpc(sep);
1012                         } else
1013 #endif
1014                         {
1015                                 uint16_t port = htons(atoi(sep->se_service));
1016                                 // FIXME: atoi_or_else(str, 0) would be handy here
1017                                 if (!port) {
1018                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1019                                         if (isdigit(protoname[strlen(protoname) - 1]))
1020                                                 protoname[strlen(protoname) - 1] = '\0';
1021                                         sp = getservbyname(sep->se_service, protoname);
1022                                         if (sp == 0) {
1023                                                 bb_error_msg("%s/%s: unknown service",
1024                                                                 sep->se_service, sep->se_proto);
1025                                                 goto serv_unknown;
1026                                         }
1027                                         port = sp->s_port;
1028                                 }
1029                                 if (port != sep->se_ctrladdr_in.sin_port) {
1030                                         sep->se_ctrladdr_in.sin_port = port;
1031                                         if (sep->se_fd != -1) {
1032                                                 FD_CLR(sep->se_fd, &allsock);
1033                                                 nsock--;
1034                                                 (void) close(sep->se_fd);
1035                                         }
1036                                         sep->se_fd = -1;
1037                                 }
1038                                 if (sep->se_fd == -1)
1039                                         setup(sep);
1040                         }
1041                         break;
1042 #ifdef CONFIG_FEATURE_IPV6
1043                 case AF_INET6:
1044                         sep->se_ctrladdr_in6.sin6_family = AF_INET6;
1045                         /* se_ctrladdr_in was set in getconfigent */
1046                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in6;
1047
1048 #ifdef CONFIG_FEATURE_INETD_RPC
1049                         if (isrpcservice(sep)) {
1050                                 struct rpcent *rp;
1051
1052                                 sep->se_rpcprog = atoi(sep->se_service);
1053                                 if (sep->se_rpcprog == 0) {
1054                                         rp = getrpcbyname(sep->se_service);
1055                                         if (rp == 0) {
1056                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1057                                                 goto serv_unknown;
1058                                         }
1059                                         sep->se_rpcprog = rp->r_number;
1060                                 }
1061                                 if (sep->se_fd == -1)
1062                                         setup(sep);
1063                                 if (sep->se_fd != -1)
1064                                         register_rpc(sep);
1065                         } else
1066 #endif
1067                         {
1068                                 uint16_t port = htons(atoi(sep->se_service));
1069
1070                                 if (!port) {
1071                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1072                                         if (isdigit(protoname[strlen(protoname) - 1]))
1073                                                 protoname[strlen(protoname) - 1] = '\0';
1074                                         sp = getservbyname(sep->se_service, protoname);
1075                                         if (sp == 0) {
1076                                                 bb_error_msg("%s/%s: unknown service",
1077                                                                 sep->se_service, sep->se_proto);
1078                                                 goto serv_unknown;
1079                                         }
1080                                         port = sp->s_port;
1081                                 }
1082                                 if (port != sep->se_ctrladdr_in6.sin6_port) {
1083                                         sep->se_ctrladdr_in6.sin6_port = port;
1084                                         if (sep->se_fd != -1) {
1085                                                 FD_CLR(sep->se_fd, &allsock);
1086                                                 nsock--;
1087                                                 (void) close(sep->se_fd);
1088                                         }
1089                                         sep->se_fd = -1;
1090                                 }
1091                                 if (sep->se_fd == -1)
1092                                         setup(sep);
1093                         }
1094                         break;
1095 #endif /* CONFIG_FEATURE_IPV6 */
1096                 }
1097         serv_unknown:
1098                 if (cp->se_next != NULL) {
1099                         servtab_t *tmp = cp;
1100
1101                         cp = cp->se_next;
1102                         free(tmp);
1103                 } else {
1104                         free(cp);
1105                         cp = getconfigent();
1106                 }
1107         }
1108         endconfig();
1109         /*
1110          * Purge anything not looked at above.
1111          */
1112         Block_Using_Signals(omask);
1113         sepp = &servtab;
1114         while ((sep = *sepp)) {
1115                 if (sep->se_checked) {
1116                         sepp = &sep->se_next;
1117                         continue;
1118                 }
1119                 *sepp = sep->se_next;
1120                 if (sep->se_fd != -1) {
1121                         FD_CLR(sep->se_fd, &allsock);
1122                         nsock--;
1123                         (void) close(sep->se_fd);
1124                 }
1125 #ifdef CONFIG_FEATURE_INETD_RPC
1126                 if (isrpcservice(sep))
1127                         unregister_rpc(sep);
1128 #endif
1129                 if (sep->se_family == AF_UNIX)
1130                         (void) unlink(sep->se_service);
1131                 freeconfig(sep);
1132                 free(sep);
1133         }
1134         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1135 }
1136
1137
1138 static void reapchild(int sig ATTRIBUTE_UNUSED)
1139 {
1140         pid_t pid;
1141         int save_errno = errno, status;
1142         servtab_t *sep;
1143
1144         for (;;) {
1145                 pid = wait3(&status, WNOHANG, NULL);
1146                 if (pid <= 0)
1147                         break;
1148                 for (sep = servtab; sep; sep = sep->se_next)
1149                         if (sep->se_wait == pid) {
1150                                 if (WIFEXITED(status) && WEXITSTATUS(status))
1151                                         bb_error_msg("%s: exit status 0x%x",
1152                                                         sep->se_server, WEXITSTATUS(status));
1153                                 else if (WIFSIGNALED(status))
1154                                         bb_error_msg("%s: exit signal 0x%x",
1155                                                         sep->se_server, WTERMSIG(status));
1156                                 sep->se_wait = 1;
1157                                 FD_SET(sep->se_fd, &allsock);
1158                                 nsock++;
1159                         }
1160         }
1161         errno = save_errno;
1162 }
1163
1164 static void retry(int sig ATTRIBUTE_UNUSED)
1165 {
1166         servtab_t *sep;
1167
1168         timingout = 0;
1169         for (sep = servtab; sep; sep = sep->se_next) {
1170                 if (sep->se_fd == -1) {
1171                         switch (sep->se_family) {
1172                         case AF_UNIX:
1173                         case AF_INET:
1174 #ifdef CONFIG_FEATURE_IPV6
1175                         case AF_INET6:
1176 #endif
1177                                 setup(sep);
1178 #ifdef CONFIG_FEATURE_INETD_RPC
1179                                 if (sep->se_fd != -1 && isrpcservice(sep))
1180                                         register_rpc(sep);
1181 #endif
1182                                 break;
1183                         }
1184                 }
1185         }
1186 }
1187
1188 static void goaway(int sig ATTRIBUTE_UNUSED)
1189 {
1190         servtab_t *sep;
1191
1192         /* XXX signal race walking sep list */
1193         for (sep = servtab; sep; sep = sep->se_next) {
1194                 if (sep->se_fd == -1)
1195                         continue;
1196
1197                 switch (sep->se_family) {
1198                 case AF_UNIX:
1199                         (void) unlink(sep->se_service);
1200                         break;
1201                 case AF_INET:
1202 #ifdef CONFIG_FEATURE_IPV6
1203                 case AF_INET6:
1204 #endif
1205 #ifdef CONFIG_FEATURE_INETD_RPC
1206                         if (sep->se_wait == 1 && isrpcservice(sep))
1207                                 unregister_rpc(sep);   /* XXX signal race */
1208 #endif
1209                         break;
1210                 }
1211                 (void) close(sep->se_fd);
1212         }
1213         (void) unlink(_PATH_INETDPID);
1214         exit(0);
1215 }
1216
1217
1218 #ifdef INETD_SETPROCTITLE
1219 static char **Argv;
1220 static char *LastArg;
1221
1222 static void
1223 inetd_setproctitle(char *a, int s)
1224 {
1225         socklen_t size;
1226         char *cp;
1227         struct sockaddr_in prt_sin;
1228         char buf[80];
1229
1230         cp = Argv[0];
1231         size = sizeof(prt_sin);
1232         (void) snprintf(buf, sizeof buf, "-%s", a);
1233         if (getpeername(s, (struct sockaddr *) &prt_sin, &size) == 0) {
1234                 char *sa = inet_ntoa(prt_sin.sin_addr);
1235
1236                 buf[sizeof(buf) - 1 - strlen(sa) - 3] = '\0';
1237                 strcat(buf, " [");
1238                 strcat(buf, sa);
1239                 strcat(buf, "]");
1240         }
1241         strncpy(cp, buf, LastArg - cp);
1242         cp += strlen(cp);
1243         while (cp < LastArg)
1244                 *cp++ = ' ';
1245 }
1246 #endif
1247
1248
1249 int
1250 inetd_main(int argc, char *argv[])
1251 {
1252         servtab_t *sep;
1253         struct passwd *pwd;
1254         struct group *grp = NULL;
1255         int tmpint;
1256         struct sigaction sa, sapipe;
1257         int opt;
1258         pid_t pid;
1259         char buf[50];
1260         char *stoomany;
1261         sigset_t omask, wait_mask;
1262
1263 #ifdef INETD_SETPROCTITLE
1264         extern char **environ;
1265         char **envp = environ;
1266
1267         Argv = argv;
1268         if (envp == 0 || *envp == 0)
1269                 envp = argv;
1270         while (*envp)
1271                 envp++;
1272         LastArg = envp[-1] + strlen(envp[-1]);
1273 #endif
1274
1275         openlog(applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
1276
1277         opt = getopt32(argc, argv, "R:f", &stoomany);
1278         if(opt & 1) {
1279                 toomany = xatoi_u(stoomany);
1280         }
1281         argc -= optind;
1282         argv += optind;
1283
1284         uid = getuid();
1285         if (uid != 0)
1286                 CONFIG = NULL;
1287         if (argc > 0)
1288                 CONFIG = argv[0];
1289         if (CONFIG == NULL)
1290                 bb_error_msg_and_die("non-root must specify a config file");
1291
1292 #ifdef BB_NOMMU
1293         if (!(opt & 2)) {
1294                 /* reexec for vfork() do continue parent */
1295                 vfork_daemon_rexec(0, 0, argc, argv, "-f");
1296         }
1297         bb_sanitize_stdio(0);
1298 #else
1299         bb_sanitize_stdio(!(opt & 2));
1300 #endif
1301         logmode = LOGMODE_SYSLOG;
1302
1303         if (uid == 0) {
1304                 /* If run by hand, ensure groups vector gets trashed */
1305                 gid_t gid = getgid();
1306                 setgroups(1, &gid);
1307         }
1308
1309         {
1310                 FILE *fp = fopen(_PATH_INETDPID, "w");
1311                 if (fp != NULL) {
1312                         fprintf(fp, "%u\n", getpid());
1313                         fclose(fp);
1314                 }
1315         }
1316
1317         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
1318                 bb_perror_msg("getrlimit");
1319         } else {
1320                 rlim_ofile_cur = rlim_ofile.rlim_cur;
1321                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
1322                         rlim_ofile_cur = OPEN_MAX;
1323         }
1324
1325         memset((char *) &sa, 0, sizeof(sa));
1326         sigemptyset(&sa.sa_mask);
1327         sigaddset(&sa.sa_mask, SIGALRM);
1328         sigaddset(&sa.sa_mask, SIGCHLD);
1329         sigaddset(&sa.sa_mask, SIGHUP);
1330         sa.sa_handler = retry;
1331         sigaction(SIGALRM, &sa, NULL);
1332         config(SIGHUP);
1333         sa.sa_handler = config;
1334         sigaction(SIGHUP, &sa, NULL);
1335         sa.sa_handler = reapchild;
1336         sigaction(SIGCHLD, &sa, NULL);
1337         sa.sa_handler = goaway;
1338         sigaction(SIGTERM, &sa, NULL);
1339         sa.sa_handler = goaway;
1340         sigaction(SIGINT, &sa, NULL);
1341         sa.sa_handler = SIG_IGN;
1342         sigaction(SIGPIPE, &sa, &sapipe);
1343         memset(&wait_mask, 0, sizeof(wait_mask));
1344         {
1345                 /* space for daemons to overwrite environment for ps */
1346 #define DUMMYSIZE       100
1347                 char dummy[DUMMYSIZE];
1348
1349                 (void) memset(dummy, 'x', DUMMYSIZE - 1);
1350                 dummy[DUMMYSIZE - 1] = '\0';
1351
1352                 (void) setenv("inetd_dummy", dummy, 1);
1353         }
1354
1355         for (;;) {
1356                 int n, ctrl = -1;
1357                 fd_set readable;
1358
1359                 if (nsock == 0) {
1360                         Block_Using_Signals(omask);
1361                         while (nsock == 0)
1362                                 sigsuspend(&wait_mask);
1363                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1364                 }
1365
1366                 readable = allsock;
1367                 n = select(maxsock + 1, &readable, NULL, NULL, NULL);
1368                 if (n <= 0) {
1369                         if (n < 0 && errno != EINTR) {
1370                                 bb_perror_msg("select");
1371                                 sleep(1);
1372                         }
1373                         continue;
1374                 }
1375
1376                 for (sep = servtab; n && sep; sep = sep->se_next) {
1377                         if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1378                                 continue;
1379
1380                         n--;
1381                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
1382                                 ctrl = accept(sep->se_fd, NULL, NULL);
1383                                 if (ctrl < 0) {
1384                                         if (errno == EINTR)
1385                                                 continue;
1386                                         bb_perror_msg("accept (for %s)", sep->se_service);
1387                                         continue;
1388                                 }
1389                                 if (sep->se_family == AF_INET && sep->se_socktype == SOCK_STREAM) {
1390                                         struct sockaddr_in peer;
1391                                         socklen_t plen = sizeof(peer);
1392
1393                                         if (getpeername(ctrl, (struct sockaddr *) &peer, &plen) < 0) {
1394                                                 bb_error_msg("cannot getpeername");
1395                                                 close(ctrl);
1396                                                 continue;
1397                                         }
1398                                         if (ntohs(peer.sin_port) == 20) {
1399                                                 /* XXX ftp bounce */
1400                                                 close(ctrl);
1401                                                 continue;
1402                                         }
1403                                 }
1404                         } else
1405                                 ctrl = sep->se_fd;
1406
1407                         Block_Using_Signals(omask);
1408                         pid = 0;
1409 #ifdef INETD_FEATURE_ENABLED
1410                         if (sep->se_bi == 0 || sep->se_bi->bi_fork)
1411 #endif
1412                         {
1413                                 if (sep->se_count++ == 0)
1414                                         (void) gettimeofday(&sep->se_time, NULL);
1415                                 else if (toomany > 0 && sep->se_count >= sep->se_max) {
1416                                         struct timeval now;
1417
1418                                         (void) gettimeofday(&now, NULL);
1419                                         if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL) {
1420                                                 sep->se_time = now;
1421                                                 sep->se_count = 1;
1422                                         } else {
1423                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1424                                                         close(ctrl);
1425                                                 if (sep->se_family == AF_INET &&
1426                                                           ntohs(sep->se_ctrladdr_in.sin_port) >= IPPORT_RESERVED) {
1427                                                         /*
1428                                                          * Cannot close it -- there are
1429                                                          * thieves on the system.
1430                                                          * Simply ignore the connection.
1431                                                          */
1432                                                         --sep->se_count;
1433                                                         continue;
1434                                                 }
1435                                                 bb_error_msg("%s/%s server failing (looping), service terminated",
1436                                                               sep->se_service, sep->se_proto);
1437                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1438                                                         close(ctrl);
1439                                                 FD_CLR(sep->se_fd, &allsock);
1440                                                 (void) close(sep->se_fd);
1441                                                 sep->se_fd = -1;
1442                                                 sep->se_count = 0;
1443                                                 nsock--;
1444                                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1445                                                 if (!timingout) {
1446                                                         timingout = 1;
1447                                                         alarm(RETRYTIME);
1448                                                 }
1449                                                 continue;
1450                                         }
1451                                 }
1452                                 pid = fork();
1453                         }
1454                         if (pid < 0) {
1455                                 bb_perror_msg("fork");
1456                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1457                                         close(ctrl);
1458                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1459                                 sleep(1);
1460                                 continue;
1461                         }
1462                         if (pid && sep->se_wait) {
1463                                 sep->se_wait = pid;
1464                                 FD_CLR(sep->se_fd, &allsock);
1465                                 nsock--;
1466                         }
1467                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1468                         if (pid == 0) {
1469 #ifdef INETD_FEATURE_ENABLED
1470                                 if (sep->se_bi) {
1471                                         (*sep->se_bi->bi_fn)(ctrl, sep);
1472                                 } else
1473 #endif
1474                                         {
1475                                         pwd = getpwnam(sep->se_user);
1476                                         if (pwd == NULL) {
1477                                                 bb_error_msg("getpwnam: %s: no such user", sep->se_user);
1478                                                 goto do_exit1;
1479                                         }
1480                                         if (setsid() < 0)
1481                                                 bb_perror_msg("%s: setsid", sep->se_service);
1482                                         if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1483                                                 bb_error_msg("getgrnam: %s: no such group", sep->se_group);
1484                                                 goto do_exit1;
1485                                         }
1486                                         if (uid != 0) {
1487                                                 /* a user running private inetd */
1488                                                 if (uid != pwd->pw_uid)
1489                                                         _exit(1);
1490                                         } else if (pwd->pw_uid) {
1491                                                 if (sep->se_group)
1492                                                         pwd->pw_gid = grp->gr_gid;
1493                                                 xsetgid((gid_t) pwd->pw_gid);
1494                                                 initgroups(pwd->pw_name, pwd->pw_gid);
1495                                                 xsetuid((uid_t) pwd->pw_uid);
1496                                         } else if (sep->se_group) {
1497                                                 xsetgid(grp->gr_gid);
1498                                                 setgroups(1, &grp->gr_gid);
1499                                         }
1500                                         dup2(ctrl, 0);
1501                                         if (ctrl) close(ctrl);
1502                                         dup2(0, 1);
1503                                         dup2(0, 2);
1504                                         if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1505                                                 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1506                                                         bb_perror_msg("setrlimit");
1507                                         closelog();
1508                                         for (tmpint = rlim_ofile_cur - 1; --tmpint > 2;)
1509                                                 (void) close(tmpint);
1510                                         sigaction(SIGPIPE, &sapipe, NULL);
1511                                         execv(sep->se_server, sep->se_argv);
1512                                         bb_perror_msg("execv %s", sep->se_server);
1513 do_exit1:
1514                                         if (sep->se_socktype != SOCK_STREAM)
1515                                                 recv(0, buf, sizeof(buf), 0);
1516                                         _exit(1);
1517                                 }
1518                         }
1519                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1520                                 close(ctrl);
1521                 } /* for (sep = servtab...) */
1522         } /* for (;;) */
1523 }
1524
1525 /*
1526  * Internet services provided internally by inetd:
1527  */
1528 #define BUFSIZE 4096
1529
1530 #if defined(CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO) || \
1531                 defined(CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN) || \
1532                 defined(CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME)
1533 static int dg_badinput(struct sockaddr_in *dg_sin)
1534 {
1535         if (ntohs(dg_sin->sin_port) < IPPORT_RESERVED)
1536                 return 1;
1537         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST))
1538                 return 1;
1539         /* XXX compare against broadcast addresses in SIOCGIFCONF list? */
1540         return 0;
1541 }
1542 #endif
1543
1544 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1545 /* Echo service -- echo data back */
1546 /* ARGSUSED */
1547 static void
1548 echo_stream(int s, servtab_t *sep)
1549 {
1550         char buffer[BUFSIZE];
1551         int i;
1552
1553         inetd_setproctitle(sep->se_service, s);
1554         while (1) {
1555                 i = read(s, buffer, sizeof(buffer));
1556                 if (i <= 0) break;
1557                 /* FIXME: this isnt correct - safe_write()? */
1558                 if (write(s, buffer, i) <= 0) break;
1559         }
1560         exit(0);
1561 }
1562
1563 /* Echo service -- echo data back */
1564 /* ARGSUSED */
1565 static void
1566 echo_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1567 {
1568         char buffer[BUFSIZE];
1569         int i;
1570         socklen_t size;
1571         /* struct sockaddr_storage ss; */
1572         struct sockaddr sa;
1573
1574         size = sizeof(sa);
1575         i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size);
1576         if (i < 0)
1577                 return;
1578         if (dg_badinput((struct sockaddr_in *) &sa))
1579                 return;
1580         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1581 }
1582 #endif  /* CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1583
1584 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1585 /* Discard service -- ignore data */
1586 /* ARGSUSED */
1587 static void
1588 discard_stream(int s, servtab_t *sep)
1589 {
1590         char buffer[BUFSIZE];
1591
1592         inetd_setproctitle(sep->se_service, s);
1593         while (1) {
1594                 errno = 0;
1595                 if (read(s, buffer, sizeof(buffer)) <= 0 && errno != EINTR)
1596                         exit(0);
1597         }
1598 }
1599
1600 /* Discard service -- ignore data */
1601 /* ARGSUSED */
1602 static void
1603 discard_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1604 {
1605         char buffer[BUFSIZE];
1606
1607         (void) read(s, buffer, sizeof(buffer));
1608 }
1609 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1610
1611
1612 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1613 #define LINESIZ 72
1614 static char ring[128];
1615 static char *endring;
1616
1617 static void
1618 initring(void)
1619 {
1620         int i;
1621
1622         endring = ring;
1623
1624         for (i = 0; i <= 128; ++i)
1625                 if (isprint(i))
1626                         *endring++ = i;
1627 }
1628
1629 /* Character generator */
1630 /* ARGSUSED */
1631 static void
1632 chargen_stream(int s, servtab_t *sep)
1633 {
1634         char *rs;
1635         int len;
1636         char text[LINESIZ + 2];
1637
1638         inetd_setproctitle(sep->se_service, s);
1639
1640         if (!endring) {
1641                 initring();
1642                 rs = ring;
1643         }
1644
1645         text[LINESIZ] = '\r';
1646         text[LINESIZ + 1] = '\n';
1647         rs = ring;
1648         for (;;) {
1649                 len = endring - rs;
1650                 if (len >= LINESIZ)
1651                         memmove(text, rs, LINESIZ);
1652                 else {
1653                         memmove(text, rs, len);
1654                         memmove(text + len, ring, LINESIZ - len);
1655                 }
1656                 if (++rs == endring)
1657                         rs = ring;
1658                 if (write(s, text, sizeof(text)) != sizeof(text))
1659                         break;
1660         }
1661         exit(0);
1662 }
1663
1664 /* Character generator */
1665 /* ARGSUSED */
1666 static void
1667 chargen_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1668 {
1669         /* struct sockaddr_storage ss; */
1670         struct sockaddr sa;
1671         static char *rs;
1672         int len;
1673         char text[LINESIZ + 2];
1674         socklen_t size;
1675
1676         if (endring == 0) {
1677                 initring();
1678                 rs = ring;
1679         }
1680
1681         size = sizeof(sa);
1682         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1683                 return;
1684         if (dg_badinput((struct sockaddr_in *) &sa))
1685                 return;
1686
1687         if ((len = endring - rs) >= LINESIZ)
1688                 memmove(text, rs, LINESIZ);
1689         else {
1690                 memmove(text, rs, len);
1691                 memmove(text + len, ring, LINESIZ - len);
1692         }
1693         if (++rs == endring)
1694                 rs = ring;
1695         text[LINESIZ] = '\r';
1696         text[LINESIZ + 1] = '\n';
1697         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1698 }
1699 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1700
1701
1702 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1703 /*
1704  * Return a machine readable date and time, in the form of the
1705  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1706  * returns the number of seconds since midnight, Jan 1, 1970,
1707  * we must add 2208988800 seconds to this figure to make up for
1708  * some seventy years Bell Labs was asleep.
1709  */
1710
1711 static u_int machtime(void)
1712 {
1713         struct timeval tv;
1714
1715         if (gettimeofday(&tv, NULL) < 0) {
1716                 fprintf(stderr, "Unable to get time of day\n");
1717                 return 0L;
1718         }
1719         return htonl((u_int) tv.tv_sec + 2208988800UL);
1720 }
1721
1722 /* ARGSUSED */
1723 static void
1724 machtime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1725 {
1726         u_int result;
1727
1728         result = machtime();
1729         (void) write(s, (char *) &result, sizeof(result));
1730 }
1731
1732 /* ARGSUSED */
1733 static void
1734 machtime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1735 {
1736         u_int result;
1737         /* struct sockaddr_storage ss; */
1738         struct sockaddr sa;
1739         struct sockaddr_in *dg_sin;
1740         socklen_t size;
1741
1742         size = sizeof(sa);
1743         if (recvfrom(s, (char *) &result, sizeof(result), 0, &sa, &size) < 0)
1744                 return;
1745         /* if (dg_badinput((struct sockaddr *)&ss)) */
1746         dg_sin = (struct sockaddr_in *) &sa;
1747         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST) ||
1748                         ntohs(dg_sin->sin_port) < IPPORT_RESERVED / 2)
1749                 return;
1750         result = machtime();
1751         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1752 }
1753 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1754
1755
1756 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1757 /* Return human-readable time of day */
1758 /* ARGSUSED */
1759 static void daytime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1760 {
1761         char buffer[256];
1762         time_t t;
1763
1764         t = time(NULL);
1765
1766         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1767         (void) write(s, buffer, strlen(buffer));
1768 }
1769
1770 /* Return human-readable time of day */
1771 /* ARGSUSED */
1772 void
1773 daytime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1774 {
1775         char buffer[256];
1776         time_t t;
1777         /* struct sockaddr_storage ss; */
1778         struct sockaddr sa;
1779         socklen_t size;
1780
1781         t = time(NULL);
1782
1783         size = sizeof(sa);
1784         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1785                 return;
1786         if (dg_badinput((struct sockaddr_in *) &sa))
1787                 return;
1788         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1789         (void) sendto(s, buffer, strlen(buffer), 0, &sa, sizeof(sa));
1790 }
1791 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */